The 3rd U.S. Circuit Court of Appeals on Thursday said an appointment President Barack Obama made to the National Labor Relations Board was invalid, becoming the second circuit to question the validity of the labor board’s decisions.

The 102-page opinion, in a case called National Labor Relations Board v. New Vista, focused on the appointment of Craig Becker, a former board member who was appointed by Obama during a two-week Senate break in March 2010. (Becker stepped down from the board in 2012.) These breaks are often referred to as “intrasession” breaks, as opposed to intersessions, when the Senate is between sessions.

“We hold that the ‘recess of the Senate’ means only intersession breaks, and so we conclude that Member Becker’s appointment was invalid,” Judge Brooks Smith of the 3rd Circuit wrote in a 2-1 decision that Judge Franklin Van Antwerpen joined and Judge Joseph Greenaway dissented from.

The Constitution, in Article II, Section 2, provides a president with the power to submit nominations for “Ambassadors, other public Ministers and Consuls, Judges of the supreme Court, and all other Officers of the United States.” These nominations are reviewed by the Senate and must be approved by 2/3 of that chamber. This is a crucial check on executive power.

Article II, Section 3 notes that when the Senate is not in session, a president can use his power to “fill up all Vacancies that may happen.” But the Senate would still need to approve the nomination during their next session, otherwise the commission expires upon adjournment. And therein lies the problem with the moves made by President Obama — the Senate was still technically in session — making these appointments a blatant power grab.

The court case over the appointments isn’t finished. The Supreme Court is likely to hear the case this fall.